starknet_os: rename generic SHA names to SHA256

[dorimedini-starkware]

No description provided.

[reviewable-StarkWare]

This change is 

[dorimedini-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• starknet_os: rename generic SHA names to SHA256 #14205 👈 (View in Graphite)
• blockifier: sha512 syscall #14072 : 1 other dependent PR (#14073 )
• release: upgrade cairo, native, proving-utils #14200
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

[cursor]

PR Summary

Low Risk
Refactor-only renames and shared syscall structs; execution and padding logic are unchanged.

Overview
This PR renames and deduplicates SHA-related symbols so SHA-256 is explicit in the OS and syscall VM layer, while SHA-512 keeps its own names.

In blockifier, separate Sha256ProcessBlock* and Sha512ProcessBlock* request/response types are replaced by shared ShaProcessBlockRequest / ShaProcessBlockResponse (same layout for both sha256_process_block and sha512_process_block); behavior is unchanged.

In starknet_os, generic Sha2 names become Sha256: hint Sha2Finalize → Sha256Finalize, sha2_finalize → sha256_finalize, SHA2_FINALIZE → SHA256_FINALIZE, calculate_padding → calculate_sha256_padding, and const id ShaBatchSize → Sha256BatchSize. The Blake2s IV used for SHA-256 padding is imported as SHA256_IV. Hint-coverage fixtures are updated to Sha256Finalize.

Risk: Low — naming and type consolidation only; no new crypto or syscall semantics.

^{Reviewed by Cursor Bugbot for commit 0827a82. Bugbot is set up for automated code reviews on this repo. Configure here.}

[github-actions]

Artifacts upload workflows:

• Started at 2026-05-26T16:33:37Z
• Started at 2026-05-26T16:42:45Z
• Started at 2026-05-26T16:46:55Z
• Started at 2026-05-26T18:00:48Z

[Yoni-Starkware]

@Yoni-Starkware reviewed 10 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on dorimedini-starkware).